CBC · California Building Code

What is the scope of Chapter 15 and key roof assembly definitions?

Chapter 15 controls how roofs are designed and built: it defines a roof assembly (deck + covering and related layers), requires approved coverings installed per the Code and manufacturer instructions, sets flashing and reroofing rules (including when you must remove to the deck), and provides limited exceptions — see § 1501.1 and the Chapter 2 definitions for the definitive language.

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Last reviewed: July 5, 2026

What the code requires — 2–4 sentences

Chapter 15 governs the design, materials, construction and quality of roof assemblies and rooftop structures: in short, how a roof is built and what it must do (weather protection and resistance to design loads) (§ 1501.1) . The chapter requires that roof decks be covered with approved roof coverings installed per the Code and manufacturer instructions (§ 1503.1) and defines the terms “roof assembly,” “roof covering” and “roof deck” used throughout Chapter 15 (Definitions — Chapter 2) .

Requirements in detail

Scope (what Chapter 15 controls)

  • Chapter 15 “shall govern the design, materials, construction and quality of roof assemblies, and rooftop structures” — this is the controlling scope sentence to use when deciding whether Chapter 15 applies to a roof work item (§ 1501.1) .

Key definitions that affect application

  • Roof assembly (for Chapter 15): a system intended to provide weather protection and resistance to design loads; it consists of a roof covering and a roof deck, or a single component that is both; it may include underlayment, insulation, vapor retarders, etc. (Definitions — Chapter 2) .
  • Roof covering: the material applied to the roof deck for weather resistance, fire classification or appearance (Definitions — Chapter 2) .
  • Roof deck: the flat or sloped surface constructed on top of exterior walls or other supports to enclose or shelter the space below (Definitions — Chapter 2) .

These definitions are Chapter‑15–specific (note: “roof assembly” in Chapter 2 is specifically labeled “For application to Chapter 15 only”) and determine whether an element is part of the assembly or a supporting member (Definitions — Chapter 2) .

Installation and materials requirements that flow from the scope/definitions

  • Roof decks must be covered with approved roof coverings and those coverings must be secured per Chapter 15 and the manufacturer’s approved instructions (§ 1503.1) .
  • Flashing must be installed to prevent water intrusion; where metal flashing is used it must be corrosion resistant and not less than 0.019 inch thick (No. 26 galvanized) (§ 1503.2.1) .
  • The Chapter sets product-identification, materials and application requirements for roof-covering materials (§ 1506.1–1506.3) and requires roof coverings be applied per Section 1507 and manufacturer instructions (§ 1506.1, § 1507.1) .
  • When reroofing, removal to the roof deck is required for roof replacement — with specific, limited exceptions for certain adhered membranes and underlayments (§ 1512.2) .

Decision-relevant values / dimensions (quick reference)

Item Value / Requirement Code reference
Chapter scope statement Governs design, materials, construction and quality of roof assemblies and rooftop structures § 1501.1
Roof deck must be covered Roof decks shall be covered with approved roof coverings, secured per this chapter and manufacturer’s instructions § 1503.1
Metal flashing thickness Corrosion-resistant metal flashing not less than 0.019 in (No. 26 galvanized) § 1503.2.1
Reroofing — replacement removal Roof replacement requires removal of all existing layers of roof assembly materials down to the roof deck (with limited exceptions) § 1512.2
Reroofing — slope exception for recovers Exception allows existing low‑slope recover to remain without meeting 1/4:12 (2%) minimum where positive drainage exists and other conditions are met (§ 1507 referenced) § 1512.1 Exception 1 (references § 1507)

Exceptions & special cases

  • Reroofing exceptions: Recovering or replacing existing low‑slope roofs is not required to meet the 1/4 in 12 minimum slope where the roof provides positive drainage and meets Sections 1608.3 and 1611.2; similarly, existing secondary drainage elements need not be retrofitted when positive drainage exists and code conditions are met (§ 1512.1 exceptions) .
  • Limited retention of adhered membranes/underlayments: When an existing ice barrier membrane or self‑adhered underlayment is adhered to the deck and the sheathing is not water‑soaked/deteriorated, that membrane may be permitted to remain when covered per specified conditions (§ 1512.2 exceptions) .
  • Product listings and fire classification: Special roof types (BIPV, PV, vegetative roofs, etc.) are subject to their own testing/listing and additional Sections (see § 1505 subsections) — Chapter 15 treats these as roof coverings or assemblies when they serve that function (§ 1505.8–1505.10) .

If you need an absolute determination whether a particular product or installation qualifies for an exception, consult the specific subsection cited above and the manufacturer’s listed instructions; Chapter 15 is prescriptive but often refers to product listings and manufacturer approvals (§ 1506.3; § 1507.1) .

Common mistakes

  • Treating “roof covering” and “roof assembly” as interchangeable. A roof covering is the outer material; a roof assembly includes the deck plus covering and any underlayments, insulation or vapor retarder (§ 1503.1; Definitions — Chapter 2) .
  • Leaving existing layers in place during a roof replacement without checking the § 1512.2 exceptions — roof replacement normally requires removal down to the deck (§ 1512.2) .
  • Relying on “custom” flashing dimensions or non‑corrosion‑resistant metal — metal flashing must be corrosion resistant and at least 0.019 in thick where metal flashings are used (§ 1503.2.1) .
  • Failing to follow the manufacturer’s installed instructions — Chapter 15 requires installation be in accordance with this code and the manufacturer’s approved instructions (§ 1503.1; § 1507.1) .

Worked example — reroofing a single‑story house

Scenario: A homeowner has a single‑story house with a low‑slope roof (approx. 2% slope) and an existing self‑adhered underlayment over wood sheathing. They want to replace the roof covering.

Step 1 — Decide whether the work is a “replacement” or “recover”:

  • If the owner wants a full roof replacement, § 1512.2 requires removal of all existing layers of roof assembly materials down to the roof deck, unless one of the limited exceptions applies (§ 1512.2) .

Step 2 — Check exceptions:

  • If the existing self‑adhered underlayment is adhered to the deck and the sheathing is NOT water‑soaked or deteriorated, the exception permits that self‑adhered layer to remain and be covered with an additional qualifying underlayment per the Tables in § 1507 (subject to manufacturer permission) (§ 1512.2 Exceptions 2–3) .

Step 3 — Installation requirements:

  • Whether the owner performs a recover under an allowed exception or a full replacement, the roof deck must be covered with an approved roof covering and installed per the Code and the manufacturer’s instructions (§ 1503.1; § 1507.1) .
  • Use proper flashing (metal flashing ≥ 0.019 in if metal is used) and secure the covering per product listing (§ 1503.2.1; § 1506.1) .

Practical numeric outcome: If the job is a replacement for a 1,500 ft² roof, the typical requirement is to remove all roof assembly layers to the deck unless the specific exception allowing the adhered underlayment to remain applies; do not assume you can leave layers in place without confirming the § 1512.2 exception conditions and manufacturer approval (§ 1512.2) .

Related provisions (quick links)

  • § 1501.1 — Scope of Chapter 15 (design, materials, construction and quality of roof assemblies and rooftop structures)
  • § 1502.2 — Secondary (emergency overflow) drains or scuppers (roof drainage considerations referenced by reroofing exceptions)
  • § 1503.1 — Roof decks shall be covered with approved roof coverings installed per this chapter and the manufacturer’s instructions
  • § 1503.2.1 — Flashing material and minimum metal thickness (0.019 in) where metal flashing is used
  • § 1506.1–1506.3 — Materials, product identification and application requirements for roof coverings
  • § 1507.1 — Scope and installation per manufacturer instructions for roof coverings (§ 1507 tables and details govern application)
  • § 1505 (various) — Fire classification and special‑purpose roof provisions (BIPV, PV, vegetative roofs)
  • § 1512.1–1512.2 — Reroofing rules, including exceptions and removal requirements to roof deck on replacement (§ 1512)

Code references

Grounded in the retrieved California Building Code — click a citation to read the verbatim passage:

  • CBC § 1502.2 High relevance — show source text

    1||||X|X|||||||||||||||||||| |1502.2||||X|X|||||||||||||||||||| |1503.3 – 1503.4|||X|||||||||||||||||||||| |1505 – 1507|||X|||||||||||||||||||||| |1507.3.10||||||||X|X|X|X|X||X|X|||||||||| |1507.7.8||||||||X|X|X|X|X||X|X|||||||||| |1509 – 1511|||X|||||||||||||||||||||| |1511.9.6||||||X|X|||||||||||||||||| |1511.10– 1511.10.1|X|||X|X|||X|X|X|X|X||X|X|||||||||| |1512|||X|||||||||||||||||||||| |1513||||||||X|X|X|X|X||X|X||||||||||

    The state agency does not adopt sections identified by the following symbol:

    The Office of the State Fire Marshal’s adoption of this chapter or individual sections is applicable to structures regulated by other state agencies pursuant to Section 1.11.

    2025 CALIFORNIA BUILDING CODE 15-1

    on Jul 18, 2025 11:14 AM (CDT) THEREUNDER.

    15-2 2025 CALIFORNIA BUILDING CODE

    on Jul 18, 2025 11:14 AM (CDT) THEREUNDER.

    15 ROOF ASSEMBLIES AND ROOFTOP STRUCTURES

    User notes:

    About this chapter: Chapter 15 provides minimum requirements for the design and construction of roof assemblies and rooftop structures. The criteria address the weather-protective barrier at the roof and, in most circumstances, a fire-resistant barrier. The chapter is largely prescriptive in nature and is based on decades of experience with various traditional materials, but it also recognizes newer products. Section 1511 addresses rooftop structures, which include penthouses, tanks, towers and spires. Rooftop penthouses larger than prescribed in this chapter must be treated as a story under Chapter 5.

    ICC code development note: Code change proposals to sections preceded by the designation [BF] or [P] will be considered by one of the code development committees meeting during the 2024 (Group A) Code Development Cycle. All other code change proposals will be considered by a code development committee meeting during the 2025 (Group B) Code Development Cycle.

    SECTION 1501—GENERAL

    1501.1 Scope. The provisions of this chapter shall govern the design, materials, construction and quality of roof assemblies, and rooftop structures.

    SECTION 1502—ROOF DRAINAGE

    [P] 1502.1 General. Design and installation of roof drainage systems shall comply with this section, Section 1611 of this code and Chapter 11 of the California Plumbing Code .

    [P] 1502.2 Secondary (emergency overflow) drains or scuppers. Where roof drains are required, secondary (emergency overflow) roof drains or scuppers shall be provided where the roof perimeter construction extends above the roof in such a manner that water will be entrapped if the primary drains allow buildup for any reason. The installation and sizing of secondary emergency overflow drains, leaders and conductors shall comply with Section 1611 of this code and Chapter 11 of the California Plumbing Code .

  • CBC § 14-23 High relevance — show source text

    1413 [DSA-SS & DSA-SS/CC, OSHPD 1, 1R, 2, 4 & 5] Additional Requirements for Anchored and Adhered Veneer. . . . . . . . . . . . . . 14-23

    CHAPTER 15 ROOF ASSEMBLIES AND ROOFTOP

    STRUCTURES. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15-1

    1501 General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15-3

    1502 Roof Drainage. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15-3

    1503 Weather Protection. . . . . . . . . . . . . . . . . . . . . . . . . . . . 15-3

    1504 Performance Requirements . . . . . . . . . . . . . . . . . . . . 15-3

    1505 Fire Classification . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15-5

    1506 Materials. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15-6

    1507 Requirements for Roof Coverings . . . . . . . . . . . . . . . 15-7

    1508 Roof Insulation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .15-20

    1509 Roof Coatings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .15-20

    1510 Radiant Barriers Installed Above Deck . . . . . . . . . .15-21

    1511 Rooftop Structures . . . . . . . . . . . . . . . . . . . . . . . . . . .15-21

    1512 Reroofing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .15-24

    1513 [DSA-SS & DSA-SS/CC, OSHPD 1, 1R, 2, 4 & 5] Seismic Anchorage of Slate Shingle, Clay and Concrete Tile Roof Coverings. . . . . . . 15-25

    INDEX . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . INDEX-1

    HISTORY NOTE TO VOLUME 1 . . . . . . . . . . . . . . . . . . . . . .HIST-1

    VOLUME 2

    CHAPTER 16 STRUCTURAL DESIGN . . . . . . . . . . . . . . . . . .16-1

  • CBC § 1501.1 High relevance — show source text

    ICC code development note: Code change proposals to sections preceded by the designation [BF] or [P] will be considered by one of the code development committees meeting during the 2024 (Group A) Code Development Cycle. All other code change proposals will be considered by a code development committee meeting during the 2025 (Group B) Code Development Cycle.

    SECTION 1501—GENERAL

    1501.1 Scope. The provisions of this chapter shall govern the design, materials, construction and quality of roof assemblies, and rooftop structures.

    SECTION 1502—ROOF DRAINAGE

    [P] 1502.1 General. Design and installation of roof drainage systems shall comply with this section, Section 1611 of this code and Chapter 11 of the California Plumbing Code .

    [P] 1502.2 Secondary (emergency overflow) drains or scuppers. Where roof drains are required, secondary (emergency overflow) roof drains or scuppers shall be provided where the roof perimeter construction extends above the roof in such a manner that water will be entrapped if the primary drains allow buildup for any reason. The installation and sizing of secondary emergency overflow drains, leaders and conductors shall comply with Section 1611 of this code and Chapter 11 of the California Plumbing Code .

    1502.3 Gutters. Gutters and leaders placed on the outside of buildings, other than Group R-3, private garages and buildings of Type V construction, shall be of noncombustible material or not less than Schedule 40 plastic pipe.

    SECTION 1503—WEATHER PROTECTION

    1503.1 General. Roof decks shall be covered with approved roof coverings secured to the building or structure in accordance with the provisions of this chapter. Roof coverings shall be designed in accordance with this code, and installed in accordance with this code and the manufacturer’s approved instructions.

    1503.2 Flashing. Flashing shall be installed in such a manner so as to prevent water from entering the wall and roof through joints in copings, through moisture-permeable materials and at intersections with parapet walls and other penetrations through the roof plane.

    1503.2.1 Locations. Flashing shall be installed at wall and roof intersections, at gutters, wherever there is a change in roof slope or direction and around roof openings. Where flashing is of metal, the metal shall be corrosion resistant with a thickness of not less than 0.019 inch (0.483 mm) (No. 26 galvanized sheet).

    1503.3 Parapet walls. Parapet walls shall be coped or covered in accordance with Sections 1503.3.1 and 1503.3.2. The top surface of the parapet wall shall provide positive drainage.

    1503.3.1 Fire-resistance-rated parapet walls. Parapet walls required by Section 705.12 shall be coped or covered with weatherproof materials of a width not less than the thickness of the parapet wall such that the fire-resistance rating of the wall is not decreased.

    1503.3.2 Other parapet walls. Parapet walls meeting one of the exceptions in Section 705.12 shall be coped or covered with weatherproof materials of a width not less than the thickness of the parapet wall.

    1503.4 Attic and rafter ventilation. Intake and exhaust vents for ventilation of attic and enclosed rafter assemblies shall be provided in accordance with Section 1202.2 and the vent product manufacturer’s installation instructions.

  • CBC § 14-3 High relevance — show source text

    1402 Performance Requirements . . . . . . . . . . . . . . . . . . . . 14-3

    1403 Materials . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14-4

    1404 Installation of Wall Coverings. . . . . . . . . . . . . . . . . . . 14-5

    1405 Combustible Materials on the Exterior Side of

    Exterior Walls . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14-16

    1406 Metal Composite Material (MCM). . . . . . . . . . . . . . . 14-17

    1407 Exterior Insulation and Finish Systems (EIFS). . . . 14-18

    1408 High-Pressure Decorative Exterior-Grade Compact Laminates (HPL). . . . . . . . . . . . . . . . . . . 14-18

    1409 Insulated Metal Panel (IMP) . . . . . . . . . . . . . . . . . . . 14-19

    1410 Plastic Composite Decking . . . . . . . . . . . . . . . . . . . . 14-21 1411 Building-Integrated Photovoltaic (BIPV) Systems for Exterior Wall Coverings and Fenestration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14-21

    1412 Soffits and Fascias at Roof Overhangs . . . . . . . . . . 14-21

    1413 [DSA-SS & DSA-SS/CC, OSHPD 1, 1R, 2, 4 & 5] Additional Requirements for Anchored and Adhered Veneer. . . . . . . . . . . . . . 14-23

    CHAPTER 15 ROOF ASSEMBLIES AND ROOFTOP

    STRUCTURES. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15-1

    1501 General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15-3

    1502 Roof Drainage. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15-3

    1503 Weather Protection. . . . . . . . . . . . . . . . . . . . . . . . . . . . 15-3

    1504 Performance Requirements . . . . . . . . . . . . . . . . . . . . 15-3

    1505 Fire Classification . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15-5

    1506 Materials. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15-6

    1507 Requirements for Roof Coverings . . . . . . . . . . . . . . . 15-7

  • CBC § 1.11. High relevance — show source text

    Entire Chapter|X||X|||||||||||||||||||||| |Adopt Entire Chapter as
    amended (amended
    sections listed below)||||||||||||||||||||||||| |Adopt only those sections
    that are listed below||||X|X|||||||||||||||||||| |Chapter / Section||||||||||||||||||||||||| |1501||||X|X|||||||||||||||||||| |1505||||X|X|||||||||||||||||||| |1506||||X|X|||||||||||||||||||| |1508||||X|X|||||||||||||||||||| |1511||||X|X||||||||||||||||||||

    The state agency does not adopt sections identified with the following symbol: The Office of the State Fire Marshal’s adoption of this chapter or individual sections is applicable to structures regulated by other state agencies pursuant to Section 1.11.

    2025 CALIFORNIA EXISTING BUILDING CODE 15-1

    on Jul 18, 2025 11:14 AM (CDT) THEREUNDER.

    15-2 2025 CALIFORNIA EXISTING BUILDING CODE

    on Jul 18, 2025 11:14 AM (CDT) THEREUNDER.

    15 CONSTRUCTION SAFEGUARDS

    User notes:

    About this chapter: Chapter 15 looks to the construction process. Parameters are provided for demolition and for protecting adjacent property during demolition and construction. Issues such as how to provide egress and adequate water supply while the building is growing, the timing of standpipe and sprinkler installation, and protection of pedestrians are addressed. Note that this chapter is consistent with Chapter 33 of the California Building Code and Chapter 33 of the California Fire Code.

    SECTION 1501—GENERAL

    [BG] 1501.1 Scope. The provisions of this chapter shall govern safety during construction and the protection of adjacent public and private properties. Fire safety during construction shall also comply with the applicable provisions of Chapter 33 of the California Fire Code.

    [BG] 1501.2 Storage and placement of construction equipment and materials. Construction equipment and materials shall be stored and placed so as not to endanger the public, the workers or adjoining property for the duration of the construction project.

    [BS] 1501.3 Roof loads. Structural roof components shall be capable of supporting the roof-covering system and the material and equipment loads that will be encountered during installation of the system.

    [BG] 1501.4 Maintenance of exits, existing structural elements, fire protection devices and sanitary safeguards. Required exits, existing structural elements, fire protection devices and sanitary safeguards shall be maintained at all times during alterations, repairs or additions to any building or structure.

    Exceptions:

    1. Where such required elements or devices are being altered or repaired, adequate substitute provisions shall be made.
    2. Maintenance of such elements and devices is not required where the existing building is not occupied.

    [BG] 1501.5 Removal of waste materials. Waste materials shall be removed in a manner that prevents injury or damage to persons, adjoining properties and public rights-of-way.

    SECTION 1502—OWNER’S RESPONSIBILITY FOR FIRE PROTECTION

  • CBC § 2-50 High relevance — show source text

    2-50 2025 CALIFORNIA BUILDING CODE

    on Jul 18, 2025 11:14 AM (CDT) THEREUNDER.

    DEFINITIONS

    [BF] RESPONSIVE VAPOR RETARDER. A vapor retarder material complying with a vapor retarder class of Class I or II, but that also has a vapor permeance of 1 perm or greater in accordance with ASTM E96, water method (Procedure B).

    [BE] RESTRICTED ENTRANCE. An entrance that is made available for common use on a controlled basis, but not public use, and that is not a service entrance.

    [BG] RETRACTABLE AWNING. A retractable awning is a cover with a frame that retracts against a building or other structure to which it is entirely supported.

    RETROFIT. [DSA-SS, DSA-SS/CC, OSHPD 1, 1R, 2, 4 & 5] The construction of any new element or system, or the alteration of any existing element or system required to bring an existing building, or portion thereof, conforming to earlier code requirements, into conformance with standards of the currently effective California Building Standards Code.

    RISER. The upright part between two adjacent stair treads, between either an upper or lower landing and an adjacent stair tread, or between two adjacent landings.

    [BS] RISK CATEGORY. A categorization of buildings and other structures for determination of flood, wind, snow, ice and earthquake loads based on the risk associated with unacceptable performance.

    [BS] ROOF ASSEMBLY (For application to Chapter 15 only). A system designed to provide weather protection and resistance to design loads. The system consists of a roof covering and roof deck or a single component serving as both the roof covering and the roof deck. A roof assembly can include an underlayment, a thermal barrier, insulation or a vapor retarder.

    [BS] ROOF COATING. A fluid-applied, adhered coating used for roof maintenance or roof repair, or as a component of a roof covering system or roof assembly.

    [BS] ROOF COVERING. The covering applied to the roof deck for weather resistance, fire classification or appearance.

    ROOF COVERING SYSTEM. See “Roof assembly.”

    [BS] ROOF DECK. The flat or sloped surface constructed on top of the exterior walls of a building or other supports for the purpose of enclosing the story below, or sheltering an area, to protect it from the elements, not including its supporting members or vertical supports.

    ROOF DRAINAGE, POSITIVE. See “Positive roof drainage.”

    [BS] ROOF RECOVER. The process of installing an additional roof covering over a prepared existing roof covering without removing the existing roof covering.

    [BS] ROOF REPAIR. Reconstruction or renewal of any part of an existing roof for the purposes of correcting damage or restoring predamage condition.

    [BS] ROOF REPLACEMENT. The process of removing the existing roof covering, repairing any damaged substrate and installing a new roof covering.

    [BG] ROOF VENTILATION. The natural or mechanical process of supplying conditioned or unconditioned air to, or removing such air from, attics, cathedral ceilings or other enclosed spaces over which a roof assembly is installed.

  • CBC § 13-4 High relevance — show source text

    1304 Investigation and Evaluation . . . . . . . . . . . . . . . . . . . 13-4

    1305 Scoring and Evaluation . . . . . . . . . . . . . . . . . . . . . . . . 13-4

    1306 Building Score . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13-14

    1307 Evaluation of Building Safety. . . . . . . . . . . . . . . . . . 13-16

    CHAPTER 14 RELOCATED OR MOVED BUILDINGS . . . . . . 14-3

    1401 General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14-3

    1402 Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14-3

    CHAPTER 15 CONSTRUCTION SAFEGUARDS . . . . . . . . . . 15-3

    1501 General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15-3

    1502 Owner’s Responsibility for Fire Protection . . . . . . . 15-3

    1503 Sanitary. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15-4

    1504 Protection of Pedestrians . . . . . . . . . . . . . . . . . . . . . . 15-4

    1505 Protection of Adjoining Property . . . . . . . . . . . . . . . 15-5

    1506 Temporary Use of Streets, Alleys and Public Property . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15-6

    1507 Fire Extinguishers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15-6

    1508 Means of Egress. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15-6

    1509 Standpipes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15-6

    1510 Automatic Sprinkler System. . . . . . . . . . . . . . . . . . . . 15-6

    1511 Accessibility . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15-7

    1512 Water Supply for Fire Protection. . . . . . . . . . . . . . . . 15-7

    CHAPTER 16 REFERENCED STANDARDS. . . . . . . . . . . . . . 16-3

    APPENDIX A GUIDELINES FOR THE SEISMIC RETROFIT

  • CBC § 12-7 High relevance — show source text

    SFM STANDARD 12-7A-3

    12-7A-3.1 Application. The minimum design, construction and performance standards set forth herein for the exposed underside of horizontal projections such as the horizontal soffits of roof eaves, floor projections and exposed underfloor areas are those deemed necessary to establish conformance to the provisions of these regulations. Materials and assemblies that meet the performance criteria of this standard are acceptable for use as defined in the California Building Standards Code.

    12-7A-3.2 Scope. This standard evaluates the fire-resistive performance of horizontal projection assemblies including the horizontal soffits of roof eaves, floor projections and exposed underfloor areas when subjected to direct flame exposure to the underside of a horizontal projection.

    12-7A-3.3 Referenced documents.

    1. ASTM D4442, Test Methods for Direct Moisture Content Measurement of Wood and Wood-Base Materials.

    2. ASTM D4444, Test Methods for Use and Calibration of Hand-Held Moisture Meters.

    3. California Building Code, Chapter 7A.

    12-7A-3.4 Definitions.

    1. Eaves. A projecting edge of a roof that extends beyond the supporting wall as in CBC 702A “Roof Eave” or similar horizontal projection assembly.
    2. Soffit. The enclosed underside of any exterior overhanging section of a roof eave or similar horizontal projection assembly (see CBC 702A “Roof Eave Soffit”).

    12-7A-3.5 Equipment.

    1. Burner. A 12 by 12-inch (300 by 300 mm) diffusion burner shall be used. Natural gas, methane or propane shall be supplied to the burner through a metered control system. The gas supply to the burner shall produce a net heat output of 300 ± 15 kW throughout the flame exposure. Burner output can be determined from HRR or calculated from the gas flow rate, temperature and pressure.
    2. Infrared temperature analyzer (optional). Intended for monitoring the temperature change of the inside of the eaves.
    3. Moisture content. Prior to testing, all materials (lumber and soffit material) shall be conditioned to a constant weight or for a minimum of 30 days at 73 ± 4°F (23 ± 2°C) and 50 ± 5% relative humidity, whichever occurs first. Constant weight shall be defined as occurring when the change in test material weight is less than or equal to 2 percent in a 24-hour period. Lumber moisture content shall be between 8 and 12 percent (oven-dry basis) and sheathing shall not exceed 8 percent (oven-dry basis).

    12-7A-3.6 Materials.

    1. Framing. The materials used shall be representative of the grades that would be typical of eave construction and installed in the eave’s subassembly as per accepted construction practices.

    2. Soffit. Material selected for the test.

    12-7A-3.7 Test system preparation (Figure 1).

    1. Eaves fabrication. The 4-foot-wide by 2-foot (1.2 m by 0.6 m) test specimen shall be constructed to fit into a 4-foot-wide (1.2 m) space at the top of the test assembly described in SFM 12-7A-1.
  • CBC § 0.35 High relevance — show source text

    RSRS is a Roof Sheathing Ring Shank nail meeting the specifications in ASTM F1667.
    e. Tabulated fastener requirements apply where the basic wind speed,V, is less than 140 mph. For wood structural panel roof sheathing attached to gable-end roof framing and
    to intermediate supports within 48 inches of roof edges and ridges, nails shall be spaced at 4 inches on center where the basic wind speed,V, is greater than 130 mph in Expo-
    sure B or greater than 110 mph in Exposure C. Spacing exceeding 6 inches on center at intermediate supports shall be permitted where the fastening is designed per the AWC
    NDS. Where the specific gravity of the wood species used for roof framing is greater than or equal to 0.35 but less than 0.42 in accordance with AWC NDS, fastening of roof
    sheathing shall be with RSRS-03 (21/2″ × 0.131″ × 0.281″ head) nails unless alternative fastening is designed in accordance with AWC NDS. Where the specific gravity of the wood
    species used for roof framing is less than 0.35, fastening of the roof sheathing shall be designed in accordance with AWC NDS.
    f. Fastening is only permitted where the basic wind speed,V, is less than or equal to 110 mph and where fastening is to wood framing of a species with specific gravity greater
    than or equal to 0.42 in accordance with AWC NDS.
    g. Nails and staples are carbon steel meeting the specifications of ASTM F1667. Connections using nails and staples of other materials, such as stainless steel, shall be designed
    by acceptable engineering practice or approved under Section 104.2.3.|For SI: 1 inch = 25.4 mm.
    a. Nails spaced at 6 inches at intermediate supports where spans are 48 inches or more. For nailing of wood structural panel and particleboard diaphragms and shear walls, refer
    to Section 2305. Nails for wall sheathing are permitted to be common, box or casing.
    b. Spacing shall be 6 inches on center on the edges and 12 inches on center at intermediate supports for nonstructural applications. Panel supports at 16 inches (20 inches if
    strength axis in the long direction of the panel, unless otherwise marked).
    c. Where a rafter is fastened to an adjacent parallel ceiling joist in accordance with this schedule and the ceiling joist is fastened to the top plate in accordance with this schedule,
    the number of toenails in the rafter shall be permitted to be reduced by one nail.
    d. RSRS is a Roof Sheathing Ring Shank nail meeting the specifications in ASTM F1667.
    e. Tabulated fastener requirements apply where the basic wind speed,V, is less than 140 mph. For wood structural panel roof sheathing attached to gable-end roof framing and
    to intermediate supports within 48 inches of roof edges and ridges, nails shall be spaced at 4 inches on center where the basic wind speed,V, is greater than 130 mph in Expo-
    sure B or greater than 110 mph in Exposure C. Spacing exceeding 6 inches on center at intermediate supports shall be permitted where the fastening is designed per the AWC
    NDS.

  • CBC § 1505.7 Medium relevance — show source text

    [BF] 1505.7 Special purpose roofs. Special purpose wood shingle or wood shake roofing shall conform to the grading and application requirements of Section 1507.8 or 1507.9. In addition, an underlayment of [5] / 8 -inch (15.9 mm) Type X water-resistant gypsum backing board or gypsum sheathing shall be placed under minimum nominal [1] / 2 -inch-thick (12.7 mm) wood structural panel solid sheathing or 1-inch (25 mm) nominal spaced sheathing.

    [BF] 1505.8 Building-integrated photovoltaic (BIPV) systems. BIPV products installed as the roof covering shall be tested, listed and labeled for fire classification in accordance with Section 1505.1.

    [BF] 1505.9 Rooftop mounted photovoltaic (PV) panel systems. Rooftop mounted photovoltaic (PV) panel systems shall be tested, listed and identified with a fire classification in accordance with UL 2703. Listed systems shall be installed in accordance with the manufacturer’s installation instructions and their listing. The fire classification shall comply with Table 1505.1 based on the type of construction of the building.

    [BF] 1505.10 Landscaped and vegetative roofs. Landscaped and vegetative roofs shall comply with Sections 1505.1 and 1507.15. Vegetative roofs shall be installed in accordance with ANSI/SPRI VF-1.

    SECTION 1506—MATERIALS

    1506.1 Scope. The requirements set forth in this section shall apply to the application of roof-covering materials specified herein. Roof coverings shall be applied in accordance with this chapter and the roof covering listing as required by Section 1505. Installation of roof coverings shall comply with the applicable provisions of Section 1507.

    1506.2 Material specifications and physical characteristics. Roof-covering materials shall conform to the applicable standards listed in this chapter.

    15-6 2025 CALIFORNIA BUILDING CODE

    on Jul 18, 2025 11:14 AM (CDT) THEREUNDER.

    ROOF ASSEMBLIES AND ROOFTOP STRUCTURES

    1506.3 Product identification. Roof-covering materials shall be delivered in packages bearing the manufacturer’s identifying marks and approved testing agency labels required in accordance with Section 1505. Bulk shipments of materials shall be accompanied with the same information issued in the form of a certificate or on a bill of lading by the manufacturer.

    SECTION 1507—REQUIREMENTS FOR ROOF COVERINGS

    1507.1 Scope. Roof coverings shall be applied in accordance with the applicable provisions of this section and the manufacturer’s installation instructions.

  • CBC § 2.25 Medium relevance — show source text

    00|2.25|0.70|DR|3.70|1.05|DR|DR| |Minimum 33
    mil steel
    furring or
    minimum
    1x wood
    furringc|33 mil cold-
    formed steel
    stud|#10 screw|Steel thick-
    ness plus 3
    threads|16|3.85|1.45|DR|DR|3.40|DR|DR|DR| |Minimum 33
    mil steel
    furring or
    minimum
    1x wood
    furringc|33 mil cold-
    formed steel
    stud|#10 screw|Steel thick-
    ness plus 3
    threads|24|3.40|DR|DR|DR|2.70|DR|DR|DR| |Minimum 33
    mil steel
    furring or
    minimum
    1x wood
    furringc|43 mil or
    thicker cold-
    formed steel
    stud|#8 Screw|Steel thick-
    ness plus 3
    threads|12|3.00|1.80|DR|DR|3.00|0.65|DR|DR| |Minimum 33
    mil steel
    furring or
    minimum
    1x wood
    furringc|43 mil or
    thicker cold-
    formed steel
    stud|#8 Screw|Steel thick-
    ness plus 3
    threads|16|3.00|1.00|DR|DR|2.85|DR|DR|DR| |Minimum 33
    mil steel
    furring or
    minimum
    1x wood
    furringc|43 mil or
    thicker cold-
    formed steel
    stud|#8 Screw|Steel thick-
    ness plus 3
    threads|24|2.85|DR|DR|DR|2.20|DR|DR|DR| |Minimum 33
    mil steel
    furring or
    minimum
    1x wood
    furringc|43 mil or
    thicker cold-
    formed steel
    stud|#10 screw|Steel thick-
    ness plus 3
    threads|12|4.00|3.85|2.80|1.80|4.00|3.05|1.50|DR| |Minimum 33
    mil steel
    furring or
    minimum
    1x wood
    furringc|43 mil or
    thicker cold-
    formed steel
    stud|#10 screw|Steel thick-
    ness plus 3
    threads|16|4.00|3.30|1.95|0.60|4.00|2.25|DR|DR| |Minimum 33
    mil steel
    furring or
    minimum
    1x wood
    furringc|43 mil or
    thicker cold-
    formed steel
    stud|#10 screw|Steel thick-
    ness plus 3
    threads|24|4.00|2.25|DR|DR|4.00|0.65|DR|DR| |For SI: 1 inch = 25.4 mm, 1 pound per square foot (psf) = 0.0479 kPa, 1 pound per square inch = 0.00689 MPa.
    DR = Design Required, o.c. = on center.
    a. Wood furring shall be spruce-pine-fir or any softwood species with a specific gravity of 0.42 or greater.

  • CBC § 12.3 Medium relevance — show source text

    1705 A .12.3 Wind-resisting components. Periodic special inspection is required for fastening of the following systems and components:

    1. Roof covering, roof deck and roof framing connections.
    2. Exterior wall covering and wall connections to roof and floor diaphragms and framing.

    1705 A .13 Special inspections for seismic resistance. Special inspections for seismic resistance shall be required as specified in Sections 1705 A .13.1 through 1705 A .13.9, unless exempted by the exceptions of Section 1704 A .2.

    1705 A .13.1 Structural steel. Special inspections for seismic resistance shall be in accordance with Section 1705 A .13.1.1 or 1705 A .13.1.2, as applicable.

    1705 A .13.1.1 Seismic force-resisting systems. Special inspections of structural steel in the seismic force-resisting systems in buildings and structures assigned to Seismic Design Category D, E or F shall be performed in accordance with the quality assurance requirements of AISC 341 and this code.

    [DSA-SS, DSA-SS/CC] Quality assurance application is not permitted for the following AISC 341, Chapter J Sections: 1. J6 (Inspection Tasks).

    17A-16 2025 CALIFORNIA BUILDING CODE

    on Jul 18, 2025 11:14 AM (CDT) THEREUNDER.

    SPECIAL INSPECTIONS AND TESTS

    2. J7 (Welding Inspection and Nondestructive Testing). 3. J10 (Inspection of Composite Structures). 4. J11 (Inspection of H-Piles).

    Additionally, the applicable portions in Table 1705A.2.1 of the California Building Code shall apply.

    1705 A .13.1.2 Structural steel elements. Special inspections of structural steel elements in the seismic force-resisting systems of buildings and structures assigned to Seismic Design Category D, E or F other than those covered in Section 1705 A .13.1.1, including struts, collectors, chords and foundation elements, shall be performed in accordance with the quality assurance requirements of AISC 341 and this code .

    [DSA-SS, DSA-SS/CC] Quality assurance application is not permitted for the following AISC 341, Chapter J Sections: 1. J6 (Inspection Tasks). 2. J7 (Welding Inspection and Nondestructive Testing). 3. J10 (Inspection of Composite Structures). 4. J11 (Inspection of H-Piles).

    Additionally, the applicable portions in Table 1705A.2.1 of the California Building Code shall apply.

    1705 A .13.2 Structural wood. For the seismic force-resisting systems of structures assigned to Seismic Design Category D, E or F:

    1. Continuous special inspection shall be required during field gluing operations of elements of the seismic force-resisting system.
    2. Periodic special inspection shall be required for nailing, bolting, anchoring and other fastening of elements of the seismic force-resisting system, including wood shear walls, wood diaphragms, drag struts, braces, shear panels and hold-downs.

Frequently asked questions

Do the Chapter 15 definitions apply to all roofs in the Code?

Yes — the Chapter 2 definitions cited for Chapter 15 define “roof assembly,” “roof covering” and “roof deck” specifically for application to Chapter 15 and those definitions are used to determine what elements fall under Chapter 15 requirements (Definitions — Chapter 2) .

Can I leave an existing self‑adhered underlayment in place when reroofing?

Possibly — § 1512.2 contains specific exceptions allowing an existing self‑adhered underlayment or ice‑barrier membrane to remain if the sheathing is not water‑soaked/deteriorated and other conditions (including manufacturer approval) are met (§ 1512.2 exceptions) .

What’s the difference between “roof covering” and “roof assembly”?

A roof covering is the outer material applied to the deck for weather resistance and appearance; a roof assembly is the complete system (deck + covering, and may include underlayment, insulation, vapor retarders) intended to provide weather protection and load resistance (Definitions — Chapter 2) .

Are manufacturer instructions mandatory?

Yes — Chapter 15 requires roof coverings to be installed in accordance with this Code and the manufacturer’s approved instructions (§ 1503.1; § 1507.1) .

Is flashing thickness regulated?

Yes — where flashing is metal it must be corrosion resistant and at least 0.019 inch thick (No. 26 galvanized) per § 1503.2.1 (§ 1503.2.1) .

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